Reflecting Sunlight Away From Earth to Cool the Planet Could Help Some Places, Really Hurt Others

Among the more high risk methods of geoengineering, methods that reflect sunlight away from the Earth to counteract temperature rise are right up there in terms of potential unintended consequences. Well, a new piece of research from scientists at the University of Bristol and published in Geophysical Research Letters attempts to determine the effects of different levels of geoengineering on different areas of the globe. As it turns out no one level is good for everyone, even if average temperatures stabilize. The scientists looked at a variety of geoengineering strengths from very little to full strength (defined as "sufficient to return global average temperatures back to normal").

Their revealed that with increasing geoengineering strength, most regions become drier while others buck the trend and become increasingly wet. For example, the USA became drier with increasing geoengineering, and returned to normal conditions under half-strength geoengineering, whereas Australia became wetter, returning to normal conditions only for full strength geoengineering. (University of Bristol)

Complicating things--like talking about the practicality or ethics of geoengineering wasn't already complicated enough--paper lead author Pete Irvine says, "If there is a large amount of global warming in the future there would be no strength of geoengineering that would be best for everyone. Some may be better off without any geoengineering while others may do better with a large amount."

That said, paper co-author Dan Lunt notes, "Our simulations indicate that it might be possible to identify a strength of geoengineering capable of meeting multiple targets, such as maintaining a stable mass balance of the Greenland ice sheet and cooling global climate, but without reducing global precipitation below normal amounts or exposing significant fractions of the Earth to unusual climate conditions."